From owner-freebsd-arch Mon Jan 28 11:16:16 2002 Delivered-To: freebsd-arch@freebsd.org Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.86.163]) by hub.freebsd.org (Postfix) with ESMTP id 8E60C37B402 for ; Mon, 28 Jan 2002 11:16:09 -0800 (PST) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.11.6/8.11.6) with ESMTP id g0SJDF745942; Mon, 28 Jan 2002 20:13:16 +0100 (CET) (envelope-from phk@critter.freebsd.dk) To: "Kenneth D. Merry" Cc: arch@FreeBSD.ORG Subject: Re: Geom project, limited preview... In-Reply-To: Your message of "Mon, 28 Jan 2002 11:15:14 MST." <20020128111514.A3819@panzer.kdm.org> Date: Mon, 28 Jan 2002 20:13:15 +0100 Message-ID: <45940.1012245195@critter.freebsd.dk> From: Poul-Henning Kamp Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG In message <20020128111514.A3819@panzer.kdm.org>, "Kenneth D. Merry" writes: >Looks interesting. > >If you end up doing any striping, mirroring or RAID with this, I would >suggest/request you put hooks in for: > > - different on-disk metadata types. There is a specific project I've been > working on (not for FreeBSD, unfortunately) that involves changing a > software RAID implementation to have support for multiple types of on-disk > metadata. My plan was to recognize what I can, and have a way for userland to configure as well. > - support for external parity engines for RAID-5 parity calculation. (If > you do any sort of RAID-5 with this.) Well, I have no raid-5 hardware so this would probably have to be left to somebody else. >Another interesting thing you could do with this would be tied in with your >"COW" proposal. In essence, you could create a block-level checkpoint >functionality. You would have the primary device, which would continue to >receive read and write requests after the checkpoint instantiation, and >then the secondary device, where you would copy the original version of any >sectors written to the primary device after the checkpoint. Hmm, that is the reverse of what I thought it should do, but I can certainly see the point... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message